Interior rearview mirror assemblies for vehicles are typically supported at the forward portion of the passenger compartment of the vehicle by a support or linkage which is most often secured either to the inside surface of the windshield or to a mounting assembly at the forward edge of the headliner on the interior vehicle roof. In either case, a mounting assembly includes a support arm connected to the rearview mirror assembly, the support arm typically including a pair of ball pivot joints allowing adjustment of the position of the rearview mirror assembly for proper vision by various vehicle drivers. A widely used, conventional support arm is that shown in U.S. Pat. No. 4,254,931 and includes a metallic cylindrical tube receiving a ball member at each end within a polymeric ball receiving cup, the cups and ball members being separated by a coil spring which urges the cups and ball members against the crimped outer ends of the tube for proper frictional engagement. However, these rearview mirror support arms have been difficult to manufacture and have encountered numerous drawbacks in use. For example, during high volume production of such supports, it is difficult to maintain the constant, consistent torque requirements for the ball pivot joints in order to properly support the rearview mirror assembly in its cantilevered position. Once the outer tube of the conventional support arm is crimped over at its ends, it cannot be adjusted. If the frictional resistance or torque required for pivotal movement is not correct, the assembly must be scrapped. Moreover, each support arm requires a relatively large number of parts such that the arm is expensive to manufacture. In addition, since the outer tube of such assemblies is normally formed from metal, it is necessary that the tube be properly painted to match or coordinate with the interior color of the vehicle or mirror assembly or to reduce glare. Once the assembly is properly painted, handling of the assembly during manufacture, shipping and/or installation can often damage the paint, again requiring the assembly to be discarded. Further, since the internal spring of such assemblies causes the frictional resistance at the two ball joints to be interdependent on one another, it is difficult to adjust the frictional resistance of each ball joint without affecting the resistance of the other joint. Also, because of the internal structure of the prior known support arms, it has been difficult to insert electrical wiring therethrough for connection to electrical components mounted in the rearview mirror assembly. Moreover, it has been difficult to use the support arm area for support of any additional components which add weight to the overall assembly.
In addition, for heavier, more complex rearview mirror assemblies, the conventionally known mounting brackets and windshield mounting members which secure the assembly to the interior surface of the vehicle windshield have been subject to failure due to the increased weight which must be supported in cantilever fashion. Over time, during the support of such heavier rearview mirror assemblies, many prior known brackets and mounting members have suffered from adhesive failure causing the assembly to drop from the windshield area.
Accordingly, there is a need in the vehicle industry for improved support capability and versatility for interior rearview mirror assemblies which have increased complexity and weight due to the inclusion of a greater number of added feature components, as well as improved vibration performance and ease and cost of manufacture.